Few weeks ago, our database virtual machines got randomly failed. There was error message " The CPU has been disabled by the guest operating system. Power off or reset the virtual machine. " on VM events. I didn't find any abnormal on vmkernel, hostd and vm logs. Finally our Linux team identified it's a Linux kernel bug. Please refer to BUG at block/blk-core.c:NNNN! in blk_requeue_request or blk finish_request . The bug only present on RedHat 6 on ESXi 5.5 with VMware Paravirtual SCSI drivers.